If Aung San Suu Kyi is elected to Burma's parliament this Sunday, the world will inevitably ask: has Asia's Nelson Mandela finally met her President FW de Klerk? Or, if you prefer a European comparison, has Asia's Václav Havel met her Mikhail Gorbachev? Cue episode three in the "from prisoner to president" saga. I do believe that day will come, but let us have no illusions: there are still major obstacles ahead. Wisdom and strength, inside and outside Burma, will be needed to surmount them.

Whatever happens, Aung San Suu Kyi has long since earned the Havel and Mandela comparisons. Like Mandela, she has endured decades of imprisonment, emerging with an extraordinary lack of rancour. Like Havel, she has not only been her country's leading dissident but also analysed its political and social condition. Listen to the BBC Reith lectures she delivered last year. Read the personal free speech manifesto she has just contributed to the 40th anniversary issue of the magazine Index on Censorship. These are classic texts of modern dissident political writing – with a new dimension, since she speaks always as a devout Buddhist.

Intellectually and morally, there is no comparison between her and Burma's (aka Myanmar's) military leader in a civilian suit, President Thein Sein. Politically, however, the opening he has led is remarkable. Not just Aung San Suu Kyi but hundreds of other political prisoners have been released, including some from the important 88 Generation student movement and monks who were active in the "saffron revolution" of 2007. The military junta has retreated behind a cloak of civilian politics. Freedom of expression and assembly has exploded, though the legal basis for it is still insecure. Activists have been catapulted from the darkness of a prison cell to the blinding flash of paparazzi bulbs.

Remarkably, Thein Sein has risked the wrath of China, Burma's would-be big brother, by suspending construction of the Chinese-funded Myitsone hydroelectric dam. (The energy would have gone mainly to China, the environmental cost to Burma.) He has sought ceasefires with insurgent minority groups, though some armed conflict continues. The National League for Democracy (NLD) has been allowed to register as a party. In this 1 April byelection, they have put up candidates for 47 out of 48 available seats in the lower house of parliament. Large crowds hail one of those candidates as a saviour wherever she goes.

If you had told anyone this four years ago, when the supremely nonviolent, monk-led protests of 2007 had just been crushed with extreme brutality, they would not have believed you. Every velvet revolution, every negotiated transition, requires figures in both regime and opposition who are ready to take the risk of engagement. At last, Burma seems to have its two to tango.

Now for the warning notes. Both leaders are taking a big risk. The regime's chief astrologer – Burmese rulers have long favoured astrologers over economists – has reportedly predicted that president Thein Sein will fall ill this summer. That illness may be political, if the grossly self-enriched military feels its vital interests are threatened. Just a few days ago, the head of the army warned that the military's special position, enshrined in the 2008 constitution, must be respected.

For the NLD leader, the risks are also great. She recently had to suspend her campaign, apparently worn out by the heat, crowds and exertion. If some on the regime side add electoral fraud to media manipulation, what will she say? Even if the NLD gets a clean sweep of the 47, it will still only have just over 10% of a lower house dominated by a combination of the military-created Union Solidarity and Development party and 110 seats (one in four!) reserved for military appointees. The next general election is not till 2015.

Popular hopes of her miracle-working powers are exceeded only by the scale of the country's economic and social problems. Central to those problems, as in Egypt, are the economic privileges of the military. "I don't want to ask what you need before the election," she told voters at an orphanage, "but I will afterwards; I promise to come back soon." But what if she can't, being stuck in parliamentary committees in the remote, artificial government city of Naypyidaw? What if she knows the people's needs but cannot supply them? Sympathetic observers say she risks exchanging one kind of powerlessness for another.

Then there is the complex relationship with the ethnic minorities that comprise around one third of the country's population. And there is China, which is hardly going to promote the emergence of a shining, western-oriented democracy on its own doorstep.

Against this, however, there are grounds for optimism. The NLD may not have the kind of organisation the ANC had in South Africa but, as Havel showed in Czechoslovakia, mass organisations can emerge with remarkable speed in velvet revolutionary times. There is the social and moral force of the country's Buddhist monks. (I challenge any Burmese general to sneer "how many divisions has the Buddha?") The regime is clearly keen to get European and American sanctions lifted, so there is some leverage there. Then there is the country's other mighty neighbour, India, which might at long last choose to encourage next door what it practices at home: democracy. There is the popular momentum that such processes acquire, once begun. And there is The Lady herself, a treasure without price.

Astrologers do, after all, make mistakes. Even political scientists have been known to err in their predictions. On what we know today, it still looks as if her road from prison to presidency has some difficult turns and harsh gradients ahead. 2015 may be a more realistic target date than 2013. And that end will itself, as Havel and Mandela discovered, only be a beginning.